The Network Time Protocol (NTP) is used to synchronize a computer's timewith a referenced time source.

Robin Park and Dmitri Vinokurov discovered a flaw in the way ntpd handledcertain malformed NTP packets. ntpd logged information about all suchpackets and replied with an NTP packet that was treated as malformed whenreceived by another ntpd. A remote attacker could use this flaw to createan NTP packet reply loop between two ntpd servers via a malformed packetwith a spoofed source IP address and port, causing ntpd on those servers touse excessive amounts of CPU time and fill disk space with log messages.(CVE-2009-3563)

All ntp users are advised to upgrade to this updated package, whichcontains a backported patch to resolve this issue. After installing theupdate, the ntpd daemon will restart automatically.

4. Solution:

Before applying this update, make sure that all previously-releasederrata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to usethe Red Hat Network to apply this update are available athttp://kbase.redhat.com/faq/docs/DOC-11259